Scrap foam is a by-product of various molding and manufacturing techniques and processes. Many processes have been directed at specifically recycling various scrap foams such as urethane foam scraps. For example the U.S. Pat. No. 3,859,404 to Immel et al, issued Jan. 7, 1975 relates to treating plastic foam scrap material to convert it into a densified foam. The U.S. Pat. No. 3,607,999 to Corbett issued Sept. 21, 1971, relates to the recovery of thermoplastic foam scrap as extruded granules. The U.S. Pat. No. 3,080,612 to Buchmann, issued Mar. 12, 1963 relates to a process of molding foam products from waste foam materials.
Other prior art processes relate to the technique of containing a precursor material in a bag which ruptures to provide a fixed charge to a mold. For example, the U.S. Pat. No. 2,959,816 to Valentine et al, issued Nov. 15, 1960, discloses an apparatus and method for mold charging which substantially eliminates waste of casting material by utilizing a bag containing a plastisol which ruptures to provide a fixed charge to a mold. The charge does not include a precompressed foam. The U.S. Pat. No. 3,347,971 to Makowich et al, issued Oct. 17, 1967, discloses a rotational mold process in which a fixed charge of PVC particles is placed in a rotating mold to form hollow balls. The patent discusses the use of defective items which may be refragmented and remolded successively but does not disclose any steps relating to precompressing the scrap, containing the precompressed scrap and then charging a mold therewith.
Various prior art patents relate to other uses of containment bags into which foam precursors are directed. For example, the U.S. Pat. No. 4,269,890 to Breitling et al, issued May 26, 1981, discloses a process and arrangement for introducing a material such as foam into automobile body cavities by initially introducing a bag into the cavity with the bag being provided with a filler opening. A mixture of expandable components is introduced into the bag and following an expansion reaction or a setting, the foam fully fills the bag. The bag is not used to contain a compressed foam but rather as a test tube for the foaming reaction.
The U.S. Pat. No. 4,238,537 to Kerr, issued Dec. 9, 1980, discloses a rotationally molded hollow article and a process for molding the article wherein the article is formed from a mixture of plastic pellets and powder both of which are copolymers of ethylene and vinyl acetate.
The U.S. Pat. No. 4,035,462 to Lane, Jr., issued July 12, 1977, discloses a method for making hollow parts by rotationally molding cross linked polyethylene and reheating the part to expand trapped air and then rapid chilling of the part to stiffen the plastic before the trapped air cools and contracts.
Accordingly, the use of rotational molding, the use of container bags in molding processes, and the reuse of polyurethane foam are each in and of themselves known to the prior art. However, there remains the need for more efficient and less costly molding techniques which utilize scrap foam for producing foam filled plastic parts.